class MagicBox<T>(item:T) {
    private var subject:T = item
}

class Boy(val name:String, val age: Int)
class Dog(val weight:Int)

fun main() {
    val magicBox:MagicBox<Boy> = MagicBox(Boy("jack", 80))
    val magicBox1:MagicBox<Dog> = MagicBox(Dog(90))
}